Boeing, Raytheon, Northrup Grumman and other big U.S. defense contractors are now sort of comfortable hiring hackers for defense. Trouble is, they want geeks who don’t smoke weed and can pass polygraph tests.

Sometimes after a black hat gets caught, they find themselves suddenly on the white hat side with the opportunity to help government agencies or start a security company. Here are five examples of people who did just that.

Ever since Black Hat USA wrapped up last week, I’ve been thinking about the irony of attendees going into heightened security mode during the conference itself – like never connecting to open Wi-Fi or encrypting all information stored on your laptop – then likely slipping back into a more lax mode throughout the rest of the year.

Jerome Radcliffe scared a lot of people — including himself, since he is a diabetic — when he showed how easy it was to hack an insulin pump from a distance at the Black Hat security conference in Las Vegas early this month.

Thousands of security professionals, hackers, federal agents and media descended on Las Vegas this week to attend the Black Hat and Defcon conferences. The two conferences exhibit the extremes of hacker and security culture, with federal agents and major corporations descending on Black Hat in large numbers and mohawk-styled hackers and Electronic Frontier Foundation lawyers attending Defcon. It’s like the difference between law enforcement and pranksterism, where both have the object of protecting freedom.

Steven Levy wrote his first book, Hackers: Heroes of the Computer Revolution, in 1984. At the Defcon hacker conference in Las Vegas today, he talked about the word “hacker” and its origins amid a crowd of young practitioners of the craft, many of whom weren’t born when he published that book.

Microsoft’s security used to be a joke. Its operating systems were riddled with bugs that were exploited by hackers and mocked at conferences such as Black Hat, the Las Vegas confab for security technology. But yesterday, one of the independent security researchers at the conference praised Microsoft’s progress on improving security.

Diabetics beware. It is possible to hack your insulin pump, from a distance, so that it can harm you rather than save your life. Other medical devices are also vulnerable to hacking in the current age of cyber insecurity. As if patients don’t have enough to worry about.

A seasoned security hacker who spent seven months figuring out how to hack a laptop battery disclosed his findings today at the Black Hat security conference. Charlie Miller, who specializes in hacking Apple software, figured out how to remotely control a battery and do some damage to it such as “bricking it” – or incapacitating it – from afar.

When Google first started talking about its Google Chrome OS software a few years ago, one of the selling points was the promise that it would come with much better built-in security than other operating systems. Now, Chrome OS has only been commercially available for a few months, and security researchers have already figured out how to hack it.

Two do-it-yourself hackers have built an unmanned aerial vehicle that they can use to spy on computer networks from above. Created on a lark as an intellectual curiosity, the project shows that it’s not that hard to create a low-cost UAV that could do some serious damage to your neighbor’s privacy.

For many years, Apple enjoyed security through obscurity. The market share for Mac computers was so small that malware creators bypassed it to go after the much bigger target, Microsoft Windows. Not anymore.

Joseph “Cofer” Black, a counter-terrorism expert who anticipated the 9/11 attacks, warned security technology professionals today that they should prepare for cyber war and be prepared for the notion that no one will believe them when they sound the alarm about such a war.

Phillipe Courtot, chief executive of Qualys, has been singing the praises of cloud-based security for more than a decade. Now the topic is fashionable and generating a $65 million a year for his company, and Qualys announced some upgrades to its cloud security platform this week at the Black Hat security conference in Las Vegas.

Black Hat and Defcon have become the must-attend conferences for both computer security professionals and fringe hackers alike. I’ve been attending for a number of years and have always been struck by the stark contrast between the people attending, ranging from federal computer security experts on the one hand and mohawk-adorned rebellious teens on the other. (Pictured is Black Hat/Defcon founder Jeff Moss, also known as Dark Tangent). For all of our stories on Black Hat and Defcon, click here.

The problem with being private is that it increasingly means that you have to choose to drop out of society. You would never let the government put a tracking device on you, but you may be carrying a cell phone that tracks your location. You don’t want the government monitoring your internet usage, but Google collects data on you.